Modern (or near future, 10-20 years) setting. Mostly regular humans. Regular firearms.
The scene goes like this: the Big Bad Villain of the story fought the Big Good Hero in hand-to-hand combat and won. He got his trusty gun, he stands above the defeated hero, he aims his gun at him... But he cannot pull the trigger. Because deus ex machina happens and a friendly character, that was imprisoned by the Villain and freed by the Hero on his way to final battle, comes to the rescue. This character, being a psychic capable of mind-controlling (like I said, mostly regular humans), overpowers weakened Villain and forces him to stop. Then, to repay the Villain for his "hospitality", the psychic forces the Villian to raise the gun and shoot off his own arm.
So here is the question (or rather two questions).
1) Is it even possible (with modern firearms) to shoot off person's limb with a single magazine/load of any one-handed non-automatic firearm? Preferably one without extended magazine.
2) What kind of calibre/ammunition type would be required for this?
Edit: What about explosive rounds? Are there any produced for handguns? Would they be better for this task?